tbuckley/cabot-search huggingface dataset:
INNV-22. A CASE REPORT OF MULTIPLE LESIONS DISAPPEARING AFTER TMZ+TTFIELDS+ DARAFENIB AND TRAMETINIB IN A PATIENT WITH GBM
Authors: Boning Cai, Xiaodong Ma, Baoling Qu
Journal: Neuro-Oncology (2022)

Abstract A 44-year-old female patient developed the disease with left visual field defect in both eyes. Brain MRI on September 13, 2021, showed irregular masses in the right basal ganglia, thalamus, and hippocampus of temporal lobe, with the lesion extending to the right midbrain and right optic tract. On September 28, 2021, intraoperative total resection of lesions in right gyrus, hippocampus, thalamus and cingulate herniawas performed under nuclear magnetic navigation and electrophysiological detection. The pathological integration diagnosis result was glioblastoma, IDH wild type with TERT C228T mutation, chromosome 7 amplification and BRAF V600E mutation, WHO grade 4, MGMT non-methylation, postoperative visual acuity same as before. Based on the protocols and data of the clinical trials that have been conducted, and the safety of simultaneous use of TTFields during radiotherapy is controllable and patients can benefit, we started the follow-up treatment: standard TMZ (75mg/m2/d), combined with TTFields and retaining the transducer arrays placed on the shaved scalp. The dose of 60/54Gy, 30 times was selected. The application time of TTFields was relatively long throughout the radiotherapy period, and patient compliance was good, with treatment duration of about 20 hours per day. One month after conventional radiotherapy, reexamination indicated that local T1 enhanced hypersignal and PWI showed hyperperfusion. The methionine PET suggested that tumor activity might still exist. We found that the BRAF V600E mutation may provide therapeutic benefit, so this patient was treated with TMZ (standard 5/28 regimen) +TTFields+ Darafenib and Trametinib. Nearly two months after the follow-up treatment, a re-examination found a remarkable phenomenon, the multiple lesions disappeared. At present, the patient continues to be treated with TTFields for a relatively long time, and the skin side effects are only grade ONE. The combination of TTFields with targeted agents and chemotherapy brought clinical benefit to the patient with manageable adverse reactions.
CTNI-34. PRECISION NEURO-ONCOLOGY - A PILOT ANALYSIS OF PERSONALIZED TREATMENT IN RECURRENT GLIOMA
Authors: Lazaros Lazaridis, Teresa Schmidt, Christoph Oster, Tobias Blau, Daniela Pierscianek, Jens Siveke, Sebastian Bauer, Hans-Ulrich Schildhaus, Ulrich Sure, Kathy Keyvani, Christoph Kleinschnitz, Martin Stuschke, Ken Herrmann, Cornelius Deuschl, Björn Scheffler, Sied Kebir, Martin Glas
Journal: Neuro-Oncology (2022)

Abstract PURPOSE When brain cancer relapses, treatment options are scarce. The use of molecularly matched targeted therapies may provide a feasible and efficacious way to treat individual patients based on the molecular tumor profile. Since little information is available on this strategy in neuro-oncology, we retrospectively analyzed the clinical course of 41 patients who underwent advanced molecular testing at disease relapse. METHODS We performed Sanger sequencing, targeted next generation sequencing, and immunohistochemistry for analysis of potential targets, including programmed death ligand 1, cyclin D1, phosphorylated mechanistic Target of Rapamycin, telomerase reverse transcriptase promoter mutation, cyclin-dependent kinase inhibitor 2A/B deletion, or BRAF-V600E mutation. In selected patients, whole exome sequencing was conducted. RESULTS The investigation included 41 patients of which 32 had isocitrate dehydrogenase (IDH) wildtype glioblastoma. Molecular analysis revealed actionable targets in 31 of 41 tested patients and 18 patients were treated accordingly (matched therapy group). Twenty-three patients received molecularly unmatched empiric treatment (unmatched therapy group). In both groups, 16 patients were diagnosed with recurrent IDH wildtype glioblastoma. The number of severe adverse events was comparable between the therapy groups. Regarding the IDH wildtype glioblastoma patients, median progression-free survival (mPFS) and median overall survival (mOS) were longer in the matched therapy group (mPFS: 3.8 versus 2.0 months, p = 0.0057; mOS: 13.0 versus 4.3 months, p = 0.0357). CONCLUSIONS These encouraging data provide a rationale for molecularly matched targeted therapy in glioma patients. For further validation, future study designs need to additionally consider prevalence and persistence of actionable molecular alterations in patient tissue.
EXTH-18. TARGETING THE ADENOSINERGIC IMMUNE SUPPRESSION PATHWAY IN HIGH GRADE GLIOMA SYNERGIZES WITH INNATE IMMUNE CHECKPOINT BLOCKADE
Authors: Senthil Lakshmana Chetty, Yifan Liu, Allison Cole, Joselyn Cruz Cruz, Eric Hoffmeyer, Rajeev Vibhakar, Sujatha Venkataraman, Siddhartha Mitra
Journal: Neuro-Oncology (2022)

Abstract Immune response in the tumor microenvironment is modulated by the conversion of eATP to AMP to adenosine via the ecto-enzymes CD39 and CD73. Overexpression of CD73 in tumors leads to an increase in extracellular adenosine concentration and decrease in eATP, resulting in immune suppression. In this study, CD73 knockouts were created in adult and pediatric glioma cell lines (DIPG17, T3691, BT245) and used to quantify the effects of CD73 knockout on macrophage phagocytosis in the presence of extracellular AMP. In cell line DIPG17, CD73 knockout significantly increased phagocytosis with and without external AMP compared to the WT. In the WT condition, addition of AMP significantly reduced phagocytosis, while this decrease was not significant in the CD73-KO. The addition of anti-CD47 antibody significantly increased phagocytosis with external AMP in the WT condition. Similar results were obtained with cell line T3691. However, CD73 knockout combined with anti-CD47 treatment and external AMP showed significantly greater phagocytosis than the WT condition. This suggests that a combination of anti-CD73 and anti-CD47 treatment may be more effective in the tumor microenvironment. Lastly, in cell line BT245, CD73 knockout significantly increased phagocytosis as seen in the other cell lines. However, no significant difference was observed between WT and CD73-KO with extracellular AMP or anti-CD47. In vivo studies were conducted in orthotopic xenograft mouse models with DIPG17 CD73 knockout cells. Combination treatment with anti-CD47 antibody significantly decreased tumor burden and prolonged survival in the CD73-KO tumors compared to anti-CD47 treated DIPG17-WT tumors. We conclude that the CD73 adenosinergic pathway and the CD47-SIRPα pathway may present a target for immunotherapy in pediatric and adult gliomas.
INNV-33. FUNCTIONAL EX VIVO TESTING PROSPECTIVELY IDENTIFIES NEWLY DIAGNOSED GLIOBLASTOMA PATIENTS SENSITIVE TO TEMOZOLOMIDE TREATMENT IRRESPECTIVE OF MGMT METHYLATION STATUS
Authors: Tessa DesRochers, Lindsay Lipinski, Ajay Abad, Robert Fenstermaker, Andrew Fabiano, Jeffery Edenfield, Charles Kanos, Navid Redjal, Analiz Rodriguez, Alireza Mansouri, Brad Zacharia, Nicholas Butowski, Jesse Jia-Xin Liu, Seunggu Han, Mateo Ziu, Adam Cohen, Ashley Smith, Cecile Rose Vibat, Aubrey Ledford
Journal: Neuro-Oncology (2022)

Abstract Standard of care (SOC) therapy for newly diagnosed (ND) glioblastoma (GBM) patients consist of temozolomide (TMZ) concurrent with radiation therapy. It is well known that patients with an unmethylated MGMT promoter are less likely to respond to TMZ, however, this trend is not universal. We have previously shown that 3D Predict™ glioma can identify patient response to TMZ, often differentially than the methylation status would predict. Here we present expanded clinical data relating to functional ex vivo testing capable of identifying patients responsive to alkylating therapies such as TMZ, regardless of methylation status. METHODS Fresh tissue specimens taken from ND GBM patients enrolled into the 3D PREDICT clinical study were examined by 3D Predict glioma to evaluate ex vivo therapeutic response to TMZ. Overall Survival (OS) and Progression Free Survival (PFS) in patients having â‰¥ 6 months follow-up post-surgery or &amp;lt; 6 months follow up but experiencing progression/death as of September 1, 2022 will be presented. Prospective correlation of clinical response and test-predicted response will be demonstrated in this expanded cohort of ND GBM patients. IMPACT This data has the potential to change treatment for ND GBM patients by stratifying according to functional therapeutic response rather than epigenetic factors that are not completely predictive of clinical response. It is feasible that 3D Predict glioma could dramatically impact patient care by determining which unmethylated patients should be treated with TMZ, and methylated patients who would potentially derive greater benefit from clinical trials or other treatment regimens.
IMMU-41. VERSATILE MRNA-NANOPARTICLE PLATFORM TO REPROGRAM THE BRAIN TUMOR MICROENVIRONMENT AND PREDICT TREATMENT OUTCOME
Authors: Adam Grippin, Hector Mendez-Gomez, Brandon Wummer, Frances Weidert, Tyler Wildes, Kyle Dyson, Jon Dobson, Duane Mitchell, Elias Sayour
Journal: Neuro-Oncology (2022)

Abstract RNA vaccines have shown great promise as activators of immune responses against viral pathogens but their efficacy in cancer is unclear. Here, we describe a versatile, personalized mRNA-nanoparticle (RNA-NP) platform that can be customized to produce powerful anti-tumor immune activation, reprogram the brain tumor microenvironment, and predict vaccine efficacy just two days after treatment. Lipid mixtures (i.e. DOTAP, Cholesterol) with or without iron oxide nanoparticle-cores were complexed with mRNA encoding tumor antigens. Intravenous administration of RNA-NPs induced robust activation of innate immune cells resulting in prolonged survival in murine models of subcutaneous and intracranial melanoma. Inclusion of cholesterol in the lipid backbone enabled delivery of nucleic acids across the blood brain barrier and into tumor-associated myeloid cells in intracranial GL261 and KR158b tumors. These cholesterol-bearing liposomes not only activated innate immune cells in the tumor microenvironment (i.e. increased expression of CD80 and MHCII), but also enabled further manipulation of this compartment. Use of RNA-NPs to deliver siRNA targeting PD-L1 resulted in significant reduction in PD-L1 expression among tumor associated myeloid cells, leading to 37% long term survivorship in combination with systemic checkpoint blockade in an otherwise fatal model of GL261. We have also shown that IONPs incorporated into the cores of these particles enable non-invasive tracking of dendritic cells by MRI, enabling creation of a theranostic approach to: 1) enhance immunologic effects; 2) facilitate translocation across the blood-brain barrier; and 3) enable non-invasive imaging to predict response to RNA-NPs.
CSIG-07. GAIN-OF-FUNCTION MUTANT P53 REGULATES LONG-NONCODING RNAS IN GLIOBLASTOMA
Authors: Ying Zhang, Feng Yuan, Cassandra Grello, Brian Reon, Myron Gibert, Collin Dube, Anindya Dutta, Eric Holland, Roger Abounader
Journal: Neuro-Oncology (2022)

Abstract P53 is frequently mutated in most human cancers, including glioblastoma (GBM). Many p53 mutants acquire gain-of-function oncogenic effects through only partially understood mechanisms. To investigate the role of gain-of-function mutant p53 (MUT-p53) in GBM, we performed ChIP-seq of wildtype p53 (WT-p53) and MUT-p53 GBM cell lines. Among 2834 unique peaks reads in MUT-p53 cells, we found 242 long non-coding RNAs (lncRNAs) with up to 145 fold enrichment relative to WT-p53. LncRNAs regulate many molecular and cellular functions, including gene expression, cell proliferation, death, cancer stem cell renewal and differentiation. We selected lncRNAs SOX21-AS1 and LINC00643 with highly enriched binding by MUT-p53 and investigated their expressions and functions in the p53 pathway. We performed ChIP confirmation of MUT-p53 binding to the promoters of these lncRNAs. We found that these lncRNAs are deregulated in GBM and correlated with GBM patient survival in the TCGA database. To investigate the functions of these LncRNAs, we knocked down their expressions by siRNA, and found significant cell death induced by si-SOX21-AS1, but not by si-LINC00643. Overexpression of LINC00643 in GBM cells led to inhibition of GBM cell proliferation, migration, invasion and in vivo xenograft growth. LINC00643 mediated the effects of MUT-p53. Co-expression of human LINC00643 and its mouse homologous in a RCAS transgenic mouse model of GBM reduced tumor growth and improved animal survival. To elucidate the mechanisms of action of the lncRNA, we performed Chromatin Isolation by RNA purification high-throughput sequencing (CHIRP-seq) to identify its binding targets. We found that LINC00643 binds to HIF1a 5’ promoter/enhancer region. Overexpression of LINC00643 in GBM cells at hypoxia growth condition reduced HIF1a mRNA and protein expression. Our study shows for the first time that gain-of-function mutant p53 regulates a subset of lncRNAs and that the lncRNAs mediate the oncogenic effects of the MUT-p53 in GBM.
PATH-05. SEX-SPECIFIC HISTOLOGICAL FEATURES RELATED TO THE SPATIAL ORGANIZATION OF TUMOR-INFILTRATING LYMPHOCYTES PREDICT OVERALL SURVIVAL IN FEMALE GLIOBLASTOMA PATIENTS
Authors: Olivia Krebs, German Corredor, Pallavi Tiwari
Journal: Neuro-Oncology (2022)

Abstract PURPOSE Epidemiological studies suggest that biological sex influences overall survival (OS) in Glioblastoma (GBM), possibly due to immunological variances between the sexes. Further, while prognostic in other cancers, the association of tumor-infiltrating lymphocytes (TILs) to OS in GBM requires additional exploration. We hypothesize that histological features corresponding to spatial organization of TILs from within the GBM microenvironment, when evaluated in a sex-specific manner, will be associated with OS. METHODS Digitized Hematoxylin-and-Eosin (H&amp;E) slides of resected GBM tumors were collected to establish a multi-site cohort of Nf435 patients. The training set included Nf201 patients from eleven contributing sites of the Cancer Genome Atlas (TCGA). The validation set included Nf234 patients consisting of cases from two hold-out TCGA sites and the Clinical Proteomic Tumor Analysis Consortium. Each digitized H&amp;E slide was assessed for quality, followed by employing a pre-trained classifier to label TIL and non-TIL cells. Spatial features related to the connectivity of nuclei centroids and corresponding cell cluster graphs were extracted for TILs, non-TILs, and between-group interactions. These TIL-centric histological features were fed into a Cox Hazard regression model with least absolute shrinkage and selection operator feature selection, to stratify patients as low or high-risk. Survival models were evaluated using Kaplan-Meier estimates, across male, female, and combined cohorts. RESULTS Selected features (i.e., measures of area and proximity across TIL clusters) were significantly associated with OS in the validation cohort (hazard ratio (HR)=1.95, confidence interval (CI)=1.19–3.2, p=0.00278), for the female cohort. For the male cohort, the selected spatial TIL features’ association with OS for the validation cohort yielded HR=1.43, CI=0.986–2.07, p=0.0667. The spatial TIL survival validation model on the combined cohort did not yield significant survival risk stratification. CONCLUSION Our findings suggest that sex-specific TIL organization histological features may be prognostic of OS in GBM tumors, specifically for the female cohort.
CSIG-05. A GABP DOMINANT NEGATIVE APPROACH TO THE REVERSAL OF TUMOR IMMORTALITY
Authors: Nicholas Stevers, Sara Collins, Noriyuki Kasahara, Joseph F Costello
Journal: Neuro-Oncology (2022)

Abstract Immortality is a fundamental hallmark of human cancer cells and therapeutic reversal is of great interest. Telomerase Reverse Transcriptase promoter (TERTp) mutations reactivate TERT expression, the rate limiting step in telomerase activity and cellular immortality. TERTp mutations are the most common non-coding mutation across all cancer types, including glioblastoma (GBM), oligodendroglioma, medulloblastoma, and high-grade meningioma. While prior telomerase therapies lack tumor selectivity and are poorly tolerated, TERTp mutations and their regulation offer a unique opportunity for tumor specific reversal of cellular immortality. The mutations generate a de novo E26 Transformation Specific (ETS) binding motif that recruits the GA-Binding Protein (GABP) multimeric complex to reactivate TERT expression. Initially we found a GABP tetramer reactivates the mutant TERTp, suggesting targeting only the tetramer may induce telomere shortening and tumor cell death. However, through knocking out this tetramer in cell cultures, we found that the GABP dimer is upregulated and maintains TERT expression. In the absence of both the dimer and one tetramer isoform, many tumor cells senesce or undergo cell death. However, some tumor cells escape this fate via upregulation of a second GABP tetrameric paralogue that maintains TERT expression. Therefore, to block all GABP complexes with a single approach, we devised a transactivation domain null, putative dominant negative GABP subunit that ultimately could be delivered to patients via a replicating retroviral system. Introduction of the construct into TERTp mutant glioma cells significantly reduced TERT expression while not altering expression in TERTp wildtype GBM cells, suggesting tumor selectivity. TERT expression was also reduced in a second TERTp mutant tumor type. We are currently investigating the long-term effects of the dominant negative GABP on telomere length and tumor immortality. Dominant negative GABP is a promising candidate for tumor selective reversal of cellular immortality by inhibiting mutant TERTp activation by all GABP multimeric forms.
EXTH-83. DEVELOPMENTALLY REGULATED ANTIGENS FOR IMMUNOLOGIC TARGETING OF EMBRYONAL PEDIATRIC BRAIN CANCERS
Authors: Mathew Sebastian, Christina Pham, Brandon Wummer, Delaney Woodworth, Alexandra Reid, Rebecca Abraham, Jorge Gil, Jeffrey Drake, Duane Mitchell, Catherine Flores
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Mutated neoantigens have shown promise as targets for cancer immunotherapy but embryonal pediatric brain tumors with notoriously low mutational burden have more limited opportunities for neoantigen directed therapies. Evidence suggests that embryonal brain tumors such as medulloblastoma (MB) and brain stem gliomas (BSG) arise from the aberrant reactivation of fetal developmental programming. We explored the hypothesis that neonatal mouse cerebellum and brainstem express developmentally regulated proteins that could serve as potent tumor rejection antigens for a preclinical model of Group 3 MB (NSC) and H3.3K27M positive BSG (K2), respectively. We thus generated tumor-reactive T cells by using P5 cerebellum and P4 brain stem RNA as sources of antigens. P5-cerebellum-specific T cells (cDevAg-T cells) and P4-brain stem-specific T cells (bsDevAg-T cells) demonstrated effector function against respective MB and BSG tumor cells with exquisite specificity. METHODS RNA was isolated from P5 cerebellum and P4 brain stem and pulsed into bone marrow-derived dendritic cells. These were then used to in vitro activate splenocytes from previously immunized mice, generating either cDevAg-T cells or bsDevAg-T cells. In vitro functionality assays against tumor targets were conducted to determine reactivity and specificity. DevAg-T cells were used in adoptive cellular therapy in orthotopic models to determine therapeutic efficacy of DevAg-specific T cells in vivo. Results and CONCLUSIONS DevAg-T cells produce high levels of Th1-type cytokines that recognize distinct subtypes of MB and BSG, show no cross-reactivity with normal brain. Adoptive cellular therapy employing DevAg-specific T cells demonstrate a significant survival benefit in orthotopic models of established Group 3 NSC MB and H3.3K27M mutation positive BSG. Our studies demonstrate that RNA encoding non-mutated and organ-specific developmental antigens can serve as novel tumor rejection antigens for pediatric brain cancers.
STEM-13. GLIOMA STEM CELLS MIMIC REGULATORY T CELL FUNCTION TO SUPPRESS THE IMMUNE RESPONSE AND PROMOTE TUMOR PROPAGATION
Authors: Amanda Johnson, Jack Korleski, Sophie Sall, Hernando Lopez-Bertoni, John Laterra
Journal: Neuro-Oncology (2022)

Abstract The advent of immunotherapy has transformed our approach to cancer treatment; however, it is virtually ineffective in glioblastoma (GBM), the most common &amp; malignant brain cancer in adults, due in part to the inherently immunosuppressive tumor microenvironment (TME). Recent research has identified GBM cancer stem cells (GSCs) as key modulators of the TME, mainly through activation and recruitment of pro-tumor immune cells (e.g., TAMs, regulatory T-cells (Tregs), MDSCs). We identified a novel immunosuppressive phenotype whereby GSCs mimic Treg function via TGF-b type II receptor (TGFBR2) signaling to suppress the immune response with the potential to promote tumor propagation and resist immunotherapy. Preliminary experiments revealed that TGFBR2 drives GBM cells to a CD44-high, mesenchymal-like GSC state. Transgenic TGFBR2 was found to induce a Treg-like transcriptional profile defined by expression of canonical Treg effector genes (e.g., CD274, ENTPD1, NT5E, LGALS1, TGFB1, PDCD1LG2) in human GBM neurospheres. Single-cell RNA-Seq and bioinformatics analyses confirmed the presence of this TGFBR2-mediated transcriptional signature in both patient-derived GSCs and patient tumors. Notably, in silico deconvolution of bulk GBM sequencing predicts that high expression of a TGFBR2-induced transcriptome associates with an immunosuppressive TME characterized by high infiltration of pro-tumor immune cells (e.g., TAMs, neutrophils). To target this Treg-like, immunosuppressive GSC phenotype, we utilized ITD-1, a small molecule inhibitor of TGFBR2. In vitro ITD-1 treatment reduced GSC proliferation capacity and downregulated expression of CD44 and Treg effectors. In T-cell co-cultures, pre-treating GSCs with ITD-1 increased T-cell viability and T-cell-mediated tumor cell killing. Administration of ITD-1 in tumor-bearing, immunocompetent mice reduced tumor volume and increased anti-tumor immune cell infiltration relative to vehicle controls. In all, ITD-1-mediated TGFBR2 inhibition attenuates a unique, Treg-like immunosuppressive and potentially tumor-protective phenotype in GSCs. Future studies will combine ITD-1 and checkpoint inhibitor therapy in an effort to increase the efficacy of immunotherapy in GBM.